An online resize of a file system with the bigalloc feature enabled
and a 1k block size would be refused since ext4_resize_begin() did not
understand s_first_data_block is 0 for all bigalloc file systems, even
when the block size is 1k.
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Avoid growing the file system to an extent so that the last block
group is too small to hold all of the metadata that must be stored in
the block group.

This problem can be triggered with the following reproducer:

umount /mnt
mke2fs -F -m0 -b 4096 -t ext4 -O resize_inode,^has_journal \
	-E resize=1073741824 /tmp/foo.img 128M
mount /tmp/foo.img /mnt
truncate --size 1708M /tmp/foo.img
resize2fs /dev/loop0 295400
umount /mnt
e2fsck -fy /tmp/foo.img
Reported-by: NTorsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

When mounting the superblock, ext4_fill_super() calculates the free
blocks and free inodes and stores them in the superblock.  It's not
strictly necessary, since we don't use them any more, but it's nice to
keep them roughly aligned to reality.

Since it's not critical for file system correctness, the code doesn't
call ext4_commit_super().  The problem is that it's in
ext4_commit_super() that we recalculate the superblock checksum.  So
if we're not going to call ext4_commit_super(), we need to call
ext4_superblock_csum_set() to make sure the superblock checksum is
consistent.

Most of the time, this doesn't matter, since we end up calling
ext4_commit_super() very soon thereafter, and definitely by the time
the file system is unmounted.  However, it doesn't work in this
sequence:

mke2fs -Fq -t ext4 /dev/vdc 128M
mount /dev/vdc /vdc
cp xfstests/git-versions /vdc
godown /vdc
umount /vdc
mount /dev/vdc
tune2fs -l /dev/vdc

With this commit, the "tune2fs -l" no longer fails.
Reported-by: NChengguang Xu <cgxu519@gmx.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

A maliciously crafted file system can cause an overflow when the
results of a 64-bit calculation is stored into a 32-bit length
parameter.

https://bugzilla.kernel.org/show_bug.cgi?id=200623Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reported-by: NWen Xu <wen.xu@gatech.edu>
Cc: stable@vger.kernel.org

A specially crafted file system can trick empty_inline_dir() into
reading past the last valid entry in a inline directory, and then run
into the end of xattr marker. This will trigger a divide by zero
fault.  Fix this by using the size of the inline directory instead of
dir->i_size.

Also clean up error reporting in __ext4_check_dir_entry so that the
message is clearer and more understandable --- and avoids the division
by zero trap if the size passed in is zero.  (I'm not sure why we
coded it that way in the first place; printing offset % size is
actually more confusing and less useful.)

https://bugzilla.kernel.org/show_bug.cgi?id=200933Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reported-by: NWen Xu <wen.xu@gatech.edu>
Cc: stable@vger.kernel.org

If the destination of the rename(2) system call exists, the inode's
link count (i_nlinks) must be non-zero.  If it is, the inode can end
up on the orphan list prematurely, leading to all sorts of hilarity,
including a use-after-free.

https://bugzilla.kernel.org/show_bug.cgi?id=200931Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reported-by: NWen Xu <wen.xu@gatech.edu>
Cc: stable@vger.kernel.org

This suppresses some false positives in gcc 8's -Wstringop-truncation

Suggested by Miguel Ojeda (hopefully the __nonstring definition will
eventually get accepted in the compiler-gcc.h header file).
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>

The err is not used after initalization. So just remove the variable.
Signed-off-by: Nzhong jiang <zhongjiang@huawei.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Merge the duplicated complex conditions to improve code readability.
Signed-off-by: NLiu Song <liu.song11@zte.com.cn>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NJiang Biao <jiang.biao2@zte.com.cn>

'ac->ac_g_ex.fe_len' is a user-controlled value which is used in the
derivation of 'ac->ac_2order'. 'ac->ac_2order', in turn, is used to
index arrays which makes it a potential spectre gadget. Fix this by
sanitizing the value assigned to 'ac->ac2_order'.  This covers the
following accesses found with the help of smatch:

* fs/ext4/mballoc.c:1896 ext4_mb_simple_scan_group() warn: potential
  spectre issue 'grp->bb_counters' [w] (local cap)

* fs/ext4/mballoc.c:445 mb_find_buddy() warn: potential spectre issue
  'EXT4_SB(e4b->bd_sb)->s_mb_offsets' [r] (local cap)

* fs/ext4/mballoc.c:446 mb_find_buddy() warn: potential spectre issue
  'EXT4_SB(e4b->bd_sb)->s_mb_maxs' [r] (local cap)
Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NJeremy Cline <jcline@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Extended attribute names are defined to be NUL-terminated, so the name
must not contain a NUL character.  This is important because there are
places when remove extended attribute, the code uses strlen to
determine the length of the entry.  That should probably be fixed at
some point, but code is currently really messy, so the simplest fix
for now is to simply validate that the extended attributes are sane.

https://bugzilla.kernel.org/show_bug.cgi?id=200401Reported-by: NWen Xu <wen.xu@gatech.edu>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Out of memory should not be considered as critical errors; so replace
ext4_error() with ext4_warnig().
Signed-off-by: NWang Shilong <wshilong@ddn.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Whenever we hit block or inode bitmap corruptions we set
bit and then reduce this block group free inode/clusters
counter to expose right available space.

However some of ext4_mark_group_bitmap_corrupted() is called
inside group spinlock, some are not, this could make it happen
that we double reduce one block group free counters from system.

Always hold group spinlock for it could fix it, but it looks
a little heavy, we could use test_and_set_bit() to fix race
problems here.
Signed-off-by: NWang Shilong <wshilong@ddn.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

When ext4_find_entry() falls back to "searching the old fashioned
way" due to a corrupt dx dir, it needs to reset the error code
to NULL so that the nonstandard ERR_BAD_DX_DIR code isn't returned
to userspace.

https://bugzilla.kernel.org/show_bug.cgi?id=199947Reported-by: NAnatoly Trosinenko <anatoly.trosinenko@yandex.com>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Signed-off-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org

Follow the lead of xfs_break_dax_layouts() and add synchronization between
operations in ext4 which remove blocks from an inode (hole punch, truncate
down, etc.) and pages which are pinned due to DAX DMA operations.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>

Inodes using DAX should only ever have exceptional entries in their page
caches.  Make this clear by warning if the iteration in
dax_layout_busy_page() ever sees a non-exceptional entry, and by adding a
comment for the pagevec_release() call which only deals with struct page
pointers.
Signed-off-by: NRoss Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The superblock timestamp fields were enlarged by u8 to be 40 bits wide.
Update the documentation to reflect this.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Create a new top-level section for documentation of filesystem usage,
on-disk format information, and anything else.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Make use of the swap macro and remove unnecessary variable *tmp*.
This makes the code easier to read and maintain.

This code was detected with the help of Coccinelle.
Signed-off-by: NGustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

There is no check for allocation failure when duplicating
"data" in ext4_remount(). Check for failure and return
error -ENOMEM in this case.
Signed-off-by: NChengguang Xu <cgxu519@gmx.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>

Output the warning message before we clobber type and be -1 all the time.
The error message would now be

[    1.519791] EXT4-fs warning (device vdb): ext4_enable_quotas:5402:
Failed to enable quota tracking (type=0, err=-3). Please run e2fsck to fix.
Signed-off-by: NJunichi Uekawa <uekawa@google.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>

The inode timestamps use 34 bits in ext4, but the various timestamps in
the superblock are limited to 32 bits. If every user accesses these as
'unsigned', then this is good until year 2106, but it seems better to
extend this a bit further in the process of removing the deprecated
get_seconds() function.

This adds another byte for each timestamp in the superblock, making
them long enough to store timestamps beyond what is in the inodes,
which seems good enough here (in ocfs2, they are already 64-bit wide,
which is appropriate for a new layout).

I did not modify e2fsprogs, which obviously needs the same change to
actually interpret future timestamps correctly.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

jbd2 is one of the few callers of current_kernel_time64(), which
is a wrapper around ktime_get_coarse_real_ts64(). This calls the
latter directly for consistency with the rest of the kernel that
is moving to the ktime_get_ family of time accessors.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

This is the last missing piece for the inode times on 32-bit systems:
now that VFS interfaces use timespec64, we just need to stop truncating
the tv_sec values for y2038 compatibililty.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

We only care about the low 32-bit for i_dtime as explained in commit
b5f51573 ("ext4: avoid Y2038 overflow in recently_deleted()"), so
the use of get_seconds() is correct here, but that function is getting
removed in the process of the y2038 fixes, so let's use the modern
ktime_get_real_seconds() here.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

The mmp_time field is 64 bits wide, which is good, but calling
get_seconds() results in a 32-bit value on 32-bit architectures. Using
ktime_get_real_seconds() instead returns 64 bits everywhere.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Reviewed-by: NJan Kara <jack@suse.cz>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

While working on extended rand for last_error/first_error timestamps,
I noticed that the endianess is wrong; we access the little-endian
fields in struct ext4_super_block as native-endian when we print them.

This adds a special case in ext4_attr_show() and ext4_attr_store()
to byteswap the superblock fields if needed.

In older kernels, this code was part of super.c, it got moved to
sysfs.c in linux-4.4.

Cc: stable@vger.kernel.org
Fixes: 52c198c6 ("ext4: add sysfs entry showing whether the fs contains errors")
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about extended attributes from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about directory layout from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about inode data fork from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about inodes from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about the journal from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about multi-mount protection from the on-disk format
wiki page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about bitmaps from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about group descriptors from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about superblocks from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Import the chapter about high level design from the on-disk format wiki
page into the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Create the basic structure of the "new" data structures & algorithms
book to be ported over from the on-disk format wiki, and then start by
pulling in the introductory information.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>

Convert the existing ext4 documentation into rst format and link it in
with the rest of the kernel documentation.
Signed-off-by: NDarrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>